Quantum Chemical Study of the Reaction between N,O-Dimethylcarbamate and the Monomer and Dimer of Methylamine

Quantum-chemical methods B3LYP and M06 are used to study the interaction between N,O‑dimethylcarbamate and the monomer and dimer of methylamine as a model for the production of polyureas. A one-stage mechanism of interaction and a two-stage route with the formation of an intermediate containing a tetracoordinated carbon atom are both considered. The latter path is unlikely, since the formation of the intermediate is characterized by low values of the equilibrium constants. Kinetically and thermodynamically reactions with the participation of the methylamine dimer are more preferable. The kinetic preference for reactions with the participation of the methylamine dimer is due to its enhanced donor and acid-base properties, relative to the monomer. The thermodynamic preference for reactions with the methylamine dimer is due to the greater entropy of transformation, relative to the reaction with the monomer.